A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

WASP-18b; Louis Philippe Coulombe; Björn Benneke; Ryan Challener; Anjali A.A. Piette; Lindsey S. Wiser; Megan Mansfield; Ryan J. MacDonald; Hayley Beltz; Adina D. Feinstein; Michael Radica; Arjun B. Savel; Leonardo A. Dos Santos; Jacob L. Bean; Vivien Parmentier; Ian Wong; Emily Rauscher; Thaddeus D. Komacek; Eliza M.R. Kempton; Xianyu Tan; Mark Hammond; Neil T. Lewis; Michael R. Line; Elspeth K.H. Lee; Hinna Shivkumar; Ian J.M. Crossfield; Matthew C. Nixon; Benjamin V. Rackham; Hannah R. Wakeford; Luis Welbanks; Xi Zhang; Natalie M. Batalha; Zachory K. Berta-Thompson; Quentin Changeat; Jean Michel Désert; Néstor Espinoza; Jayesh M. Goyal; Joseph Harrington; Heather A. Knutson; Laura Kreidberg; Mercedes López-Morales; Avi Shporer; David K. Sing; Kevin B. Stevenson; Keshav Aggarwal; Eva Maria Ahrer; Munazza K. Alam; Taylor J. Bell; Jasmina Blecic; Claudio Caceres; Aarynn L. Carter

doi:10.1038/s41586-023-06230-1

A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

WASP-18b, Louis Philippe Coulombe, Björn Benneke, Ryan Challener, Anjali A.A. Piette, Lindsey S. Wiser, Megan Mansfield, Ryan J. MacDonald, Hayley Beltz, Adina D. Feinstein, Michael Radica, Arjun B. Savel, Leonardo A. Dos Santos, Jacob L. Bean, Vivien Parmentier, Ian Wong, Emily Rauscher, Thaddeus D. Komacek, Eliza M.R. Kempton, Xianyu TanMark Hammond, Neil T. Lewis, Michael R. Line, Elspeth K.H. Lee, Hinna Shivkumar, Ian J.M. Crossfield, Matthew C. Nixon, Benjamin V. Rackham, Hannah R. Wakeford, Luis Welbanks, Xi Zhang, Natalie M. Batalha, Zachory K. Berta-Thompson, Quentin Changeat, Jean Michel Désert, Néstor Espinoza, Jayesh M. Goyal, Joseph Harrington, Heather A. Knutson, Laura Kreidberg, Mercedes López-Morales, Avi Shporer, David K. Sing, Kevin B. Stevenson, Keshav Aggarwal, Eva Maria Ahrer, Munazza K. Alam, Taylor J. Bell, Jasmina Blecic, Claudio Caceres, Aarynn L. Carter

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Abstract

Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope^1–3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis^3–12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS¹³ instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H⁻, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H=1.03−0.51+1.11 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.

Original language	English
Pages (from-to)	292-298
Number of pages	7
Journal	Nature
Volume	620
Issue number	7973
DOIs	https://doi.org/10.1038/s41586-023-06230-1
Publication status	Published - 10 Aug 2023

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WASP-18b, Coulombe, L. P., Benneke, B., Challener, R., Piette, A. A. A., Wiser, L. S., Mansfield, M., MacDonald, R. J., Beltz, H., Feinstein, A. D., Radica, M., Savel, A. B., Dos Santos, L. A., Bean, J. L., Parmentier, V., Wong, I., Rauscher, E., Komacek, T. D., Kempton, E. M. R., ... Carter, A. L. (2023). A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b. Nature, 620(7973), 292-298. https://doi.org/10.1038/s41586-023-06230-1

@article{daf4562223b34e468da9d9d3a703c017,

title = "A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b",

abstract = "Close-in giant exoplanets with temperatures greater than 2,000 K ({\textquoteleft}ultra-hot Jupiters{\textquoteright}) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope 1–3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis 3–12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS 13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance ({\textquoteleft}metallicity{\textquoteright}, M/H=1.03−0.51+1.11 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.",

author = "WASP-18b and Coulombe, {Louis Philippe} and Bj{\"o}rn Benneke and Ryan Challener and Piette, {Anjali A.A.} and Wiser, {Lindsey S.} and Megan Mansfield and MacDonald, {Ryan J.} and Hayley Beltz and Feinstein, {Adina D.} and Michael Radica and Savel, {Arjun B.} and {Dos Santos}, {Leonardo A.} and Bean, {Jacob L.} and Vivien Parmentier and Ian Wong and Emily Rauscher and Komacek, {Thaddeus D.} and Kempton, {Eliza M.R.} and Xianyu Tan and Mark Hammond and Lewis, {Neil T.} and Line, {Michael R.} and Lee, {Elspeth K.H.} and Hinna Shivkumar and Crossfield, {Ian J.M.} and Nixon, {Matthew C.} and Rackham, {Benjamin V.} and Wakeford, {Hannah R.} and Luis Welbanks and Xi Zhang and Batalha, {Natalie M.} and Berta-Thompson, {Zachory K.} and Quentin Changeat and D{\'e}sert, {Jean Michel} and N{\'e}stor Espinoza and Goyal, {Jayesh M.} and Joseph Harrington and Knutson, {Heather A.} and Laura Kreidberg and Mercedes L{\'o}pez-Morales and Avi Shporer and Sing, {David K.} and Stevenson, {Kevin B.} and Keshav Aggarwal and Ahrer, {Eva Maria} and Alam, {Munazza K.} and Bell, {Taylor J.} and Jasmina Blecic and Claudio Caceres and Carter, {Aarynn L.}",

note = "Publisher Copyright: {\textcopyright} 2023, The Author(s).",

year = "2023",

month = aug,

day = "10",

doi = "10.1038/s41586-023-06230-1",

language = "English",

volume = "620",

pages = "292--298",

journal = "Nature",

issn = "0028-0836",

publisher = "Nature Research",

number = "7973",

}

WASP-18b, Coulombe, LP, Benneke, B, Challener, R, Piette, AAA, Wiser, LS, Mansfield, M, MacDonald, RJ, Beltz, H, Feinstein, AD, Radica, M, Savel, AB, Dos Santos, LA, Bean, JL, Parmentier, V, Wong, I, Rauscher, E, Komacek, TD, Kempton, EMR, Tan, X, Hammond, M, Lewis, NT, Line, MR, Lee, EKH, Shivkumar, H, Crossfield, IJM, Nixon, MC, Rackham, BV, Wakeford, HR, Welbanks, L, Zhang, X, Batalha, NM, Berta-Thompson, ZK, Changeat, Q, Désert, JM, Espinoza, N, Goyal, JM, Harrington, J, Knutson, HA, Kreidberg, L, López-Morales, M, Shporer, A, Sing, DK, Stevenson, KB, Aggarwal, K, Ahrer, EM, Alam, MK, Bell, TJ, Blecic, J, Caceres, C & Carter, AL 2023, 'A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b', Nature, vol. 620, no. 7973, pp. 292-298. https://doi.org/10.1038/s41586-023-06230-1

TY - JOUR

T1 - A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

AU - WASP-18b

AU - Coulombe, Louis Philippe

AU - Benneke, Björn

AU - Challener, Ryan

AU - Piette, Anjali A.A.

AU - Wiser, Lindsey S.

AU - Mansfield, Megan

AU - MacDonald, Ryan J.

AU - Beltz, Hayley

AU - Feinstein, Adina D.

AU - Radica, Michael

AU - Savel, Arjun B.

AU - Dos Santos, Leonardo A.

AU - Bean, Jacob L.

AU - Parmentier, Vivien

AU - Wong, Ian

AU - Rauscher, Emily

AU - Komacek, Thaddeus D.

AU - Kempton, Eliza M.R.

AU - Tan, Xianyu

AU - Hammond, Mark

AU - Lewis, Neil T.

AU - Line, Michael R.

AU - Lee, Elspeth K.H.

AU - Shivkumar, Hinna

AU - Crossfield, Ian J.M.

AU - Nixon, Matthew C.

AU - Rackham, Benjamin V.

AU - Wakeford, Hannah R.

AU - Welbanks, Luis

AU - Zhang, Xi

AU - Batalha, Natalie M.

AU - Berta-Thompson, Zachory K.

AU - Changeat, Quentin

AU - Désert, Jean Michel

AU - Espinoza, Néstor

AU - Goyal, Jayesh M.

AU - Harrington, Joseph

AU - Knutson, Heather A.

AU - Kreidberg, Laura

AU - López-Morales, Mercedes

AU - Shporer, Avi

AU - Sing, David K.

AU - Stevenson, Kevin B.

AU - Aggarwal, Keshav

AU - Ahrer, Eva Maria

AU - Alam, Munazza K.

AU - Bell, Taylor J.

AU - Blecic, Jasmina

AU - Caceres, Claudio

AU - Carter, Aarynn L.

PY - 2023/8/10

Y1 - 2023/8/10

N2 - Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope 1–3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis 3–12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS 13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H=1.03−0.51+1.11 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.

AB - Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble Space Telescope (HST) and Spitzer Space Telescope 1–3. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis 3–12. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS 13 instrument on the JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly attributable to H−, TiO and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy-element abundance (‘metallicity’, M/H=1.03−0.51+1.11 times solar) and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the substellar point that decreases steeply and symmetrically with longitude towards the terminators.

UR - http://www.scopus.com/inward/record.url?scp=85166512433&partnerID=8YFLogxK

U2 - 10.1038/s41586-023-06230-1

DO - 10.1038/s41586-023-06230-1

M3 - Article

C2 - 37257843

AN - SCOPUS:85166512433

SN - 0028-0836

VL - 620

SP - 292

EP - 298

JO - Nature

JF - Nature

IS - 7973

ER -

A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

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